This application relates to magnetic materials and magnetic storage media.
Magnetic materials may be used for data storage. Magnetic cards, tapes, disks, and hard drives are examples of storage devices made from various magnetic materials. In most commercial magnetic recording media, each recorded bit has two logic states “0” and “1” that are represented by two different magnetic states of the recording media. Two opposite directions of the magnetization of a magnetic domain in a magnetic material, for example, may be used for the binary states. In such a material, the density of stored information coincides with the density of the magnetic domains or “bits” carrying the information. Therefore, the size of the magnetic domains in such binary magnetic recording media dictates the storage density.
One approach to increasing the magnetic storage density is to reduce the magnetic domain size or the bit size. Many techniques may be used to achieve. For example, high-density recording materials with small domain sizes developed by Fujitsu and other companies have demonstrated storage densities at about 100 Gbit/sq. inch. A decrease in the magnetic bit size, however, may lead to a decrease in the thermal and magnetic stability of the magnetically stored information. Instability in magnetic media may be caused by various factors, including an increase in temperature and by presence of stray fields from the recording head when operating on the adjacent bits, and from the interaction with the adjacent bits.